Family pedigree data on 1178 probands are to be analyzed from a clinical epidemiological and from a genetic orientation. A subpopulation of pedigrees with a positive family history will be focused upon for the initial analysis to test specific genetic hypotheses including the generally accepted multifactorial threshold model. Previously collected data include dental casts, facial photographs, and cephalograms. The cephalograms which were collected by family groups will be analyzed to compare basi-cranial and C1 and C2 mensurational relationships. This analysis will seek variant patterns of these structures in unaffected relatives. It will also enable a comparison of methodology by measuring these structures from radiographs as well directly from digitally enhanced cephalograms.